Can my central air duct work be costing me a larg electric bill. I have a 1600 sq ft home with a 2.5 ton unit.?
Monday, March 29th, 2010 at
11:42 am
I have changed my condesoer and handiling unit but still gettin a huge electric bill. No difference since I change the units. Some A/C guy said it was my duct work in the attic and something about not enough returns…help what can i do
Filed under: Wind Power
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2.5 ton is going to run & run & run to try and cool a 1600 ft square house.
It’s too small.
I have a 1500 square ft house.My condenser is a 3 ton and my evaporator is a 3 &1/2 ton.I installed the evaporator 1/2 ton larger to get extra latent heat removal.
It works great.
your duct work may have broken down over the years. if it is flex duct it may actually have holes in it. if it is a hard duct system the insulation may be off or has broken down. with little or no insulation on the duct the heat from the attic will fill the duct with heat and when your unit comes on it will blow all the hot air into your home. if you had your units replaced they should have checked your ducts for you.
Get a home energy audit from either your own electric provider or another in your area. They will provide measurements of leakage around your doors and windows and also from your ducts. They will also compare the amount of insulation in your attic with what is now recommended for your area. We just had one performed which was free of cost due to the fact that we had duct leakage. We also then qualified for a no cost "duct seal" job via our local utility company which was having a promotion. We added some additional insulation to the attic and have already reduced our electric bills for our 2-story house.
Please install a power vent fan in attic roof and cool that attic down. Set it to come on at 80 degrees. If there was not enough return the A/C would run too cold, showing low suction pressure. Always keep filter clean and garden hose off condenser with thumb pressure to keep fins clean. If it’s a return problem they would have to over charge the system to keep the freon running above 33 degrees. Add a return then recheck suction pressure you may need a little freon removed. Your return needs to be a bigger than the starting duct. There’s a formula you add the square inches of all return grills. Say your starting duct is 10 by 20=200 sq in you need about 300 sq inches of return grills. Not the exact formula but close.